Rolling Road Surprise!
Discussion
I just dropped my standard '98 Griff 500 into Dulford Automotive for a pre Le Mans check-up/suspension overhaul and arranged to get a rolling road power run at the same time. I wanted a "before" benchmark as with 57k miles I wasn't sure it wasn't making great numbers and was fully expecting to have to change the original cam.
Shows what I know! After we'd established you need to blokes sat in the boot to stop the wheels spinning we saw 302.3bhp at 6000 rpm and 273 lb ft at 5000 rpm - all run in 4th gear (the timing was 1º out and apparently correcting this would see a chunk more torque at the expense of a little horsepower). I'm assured the RR is calibrated, accurate and consistent but either way am more happy that I had near identical runs with perfectly smooth curves, that the fuelling was good everywhere and mostly that nothing fell off! I am however slightly deaf now though.
I guess the lesson here is firstly that it's easy to believe you're losing power when in fact you're just getting complacent with it and secondly that £35 of RR time is always a sound investment before you start spending big money.
Cheers
dumbfunk
Shows what I know! After we'd established you need to blokes sat in the boot to stop the wheels spinning we saw 302.3bhp at 6000 rpm and 273 lb ft at 5000 rpm - all run in 4th gear (the timing was 1º out and apparently correcting this would see a chunk more torque at the expense of a little horsepower). I'm assured the RR is calibrated, accurate and consistent but either way am more happy that I had near identical runs with perfectly smooth curves, that the fuelling was good everywhere and mostly that nothing fell off! I am however slightly deaf now though.
I guess the lesson here is firstly that it's easy to believe you're losing power when in fact you're just getting complacent with it and secondly that £35 of RR time is always a sound investment before you start spending big money.
Cheers
dumbfunk
Some do seem to have inlet and porting mods done by TVR Power prior to car leaving factory, which would lend weight to the theory that there was a true "HC" spec engine at one time.
When mine was pulled apart, it had ported and gas flowed heads and larger trumpets(but still just slightly tapered scaffolding tubes).
I have no aftermarket induction mods and a mild cam and mine pulls similar figures (see my profile), funnily enough on the same RR.
When mine was pulled apart, it had ported and gas flowed heads and larger trumpets(but still just slightly tapered scaffolding tubes).
I have no aftermarket induction mods and a mild cam and mine pulls similar figures (see my profile), funnily enough on the same RR.
Well, I must admit that I was surprised too (although my car was a dealer demo at Henley?).
But the at-the-wheels figures were consistent with 15% or so transmission loss and Richard at Dulford who's opinion I fully trust tells me it's bang on so who am I to argue! It was the shape of the curve that pleased me more than the top number though:
Anyone else used that RR?
dumbfunk
But the at-the-wheels figures were consistent with 15% or so transmission loss and Richard at Dulford who's opinion I fully trust tells me it's bang on so who am I to argue! It was the shape of the curve that pleased me more than the top number though:
Anyone else used that RR?
dumbfunk
Edited by dumbfunk on Thursday 31st May 10:04
Whether the figures are correct or not, the shape of the curve v engine speed will be and it does seem to hang on to the power at the upper end rather well. Doesn't seem to run out of steam. Are you sure it's all standard inside? If you hadn't mentioned it being standard I'd have thought maybe there was perhaps a 404 cam lurking in there with those BHP/Tq figures.
2Munkys said:
Whether the figures are correct or not, the shape of the curve v engine speed will be and it does seem to hang on to the power at the upper end rather well. Doesn't seem to run out of steam. Are you sure it's all standard inside? If you hadn't mentioned it being standard I'd have thought maybe there was perhaps a 404 cam lurking in there with those BHP/Tq figures.
Spot on Monky Boy 
that's what i think 
As far as I'm aware the car is standard other than a higher quality induction pipe and filter replacing the original cracked Ferrero Rocher spec corrugated one. I bought the car at 26k miles (1 owner + dealer demo fitted with full harness if that's in any way significant) and to be honest whilst it has always run perfectly I booked the RR session because I had my doubts that it was making the power. In fact I expected to be posting questions on what cam to choose to replace the somewhat ticky original one rather than this!
It doesn't feel *overly* ballistic on the road but I guess that has to be a combination of the smooth delivery as indicated in the curve above and the crappy S03s that spin all the time. Still not sure I believe it but I've run out of excuses to bitch now!
Oh well, cam money has gone into Superflex bushes and Nitrons so it's all good.
Roll on Le Mans!
dumbfunk
It doesn't feel *overly* ballistic on the road but I guess that has to be a combination of the smooth delivery as indicated in the curve above and the crappy S03s that spin all the time. Still not sure I believe it but I've run out of excuses to bitch now!
Oh well, cam money has gone into Superflex bushes and Nitrons so it's all good.
Roll on Le Mans!
dumbfunk
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